At present, scientific technology has become increasingly indispensable to people's normal lives in that smart phones, notebook computers and tablet computers have been widely used almost everywhere, thus scientific products are all developing with trend of both smaller size and intelligent system. A wearable scientific product refers to a wearable object incorporated with part of functions of conventional devices. Such wearable scientific product allows more closely bonding a human body with machines and releasing the human body to the largest extent. However, existing projection ring that incorporates a projector into a ring often has difficulty in adjusting projection location, and thus is not conveniently operable enough.